Influence of thermomechanical processing on the structure and properties of Cu-Ag alloy in situ composites

The influences of the thermomechanical processing, including the solidification conditions, the cold deformation and the intermediate annealing treatment, on the structure and properties of the Cu-10Ag alloy in situ composite were studied in this paper. The cast structure and the structural changes in the cold deformation and intermediate annealing process were observed. The properties including the ultimate tensile strength (UTS) and the electrical conductivity were determined. A two-stage strain strengthening effect for the Cu-10Ag alloy in situ filamentary composite was observed. The factors influencing the UTS and conductivity were discussed. The solidification conditions in the range of 10-1000 K/s cooling rates and the intermediate heat treatment showed obviously influence on the structure and properties on the Cu-10Ag alloy in situ filamentary composite. The typical properties of the Cu-Ag alloy in situ filamentary composites through thermomechanical processing were reported.     

Influence of thermomechanical processing on the structure and properties of Cu-Ag alloy in situ composites

1IntroductionTheinsitucomposites based on copper alloys with high strength and high electrical conductivity hasbeen developed for applications such as high field magnets,where the tensile strengths in excess of1GPaand electric conductivity above50%IACS(International Annealed Copper Standard)are required[1-5].TheCu alloys included essentially two types:one is the alloy system of Cu with face-centered-cubic(fcc)ele-ments such as Ag,another is the alloy systemof Cu with body-centered-cubic(b…     

Al-Cu-Mg合金析出相的原子成键与性能

根据固体与分子经验电子理论（EET），计算Al-Cu-Mg合金时效初期形成的GPB区和S″相的价电子结构。结果表明，GPB区具有较强的共价键络，而S″具有较强的总共价成键能，这两种析出相的主体共价键络都对合金基体具有增强作用。同时从价电子结构层次和析出相中Al原子的总成键能力合理解释了GPB区演化为S和S相的相变机理，并说明了相变对合金的强化作用。     

复合变质剂对ZL101铝合金力学及电化学腐蚀性能的影响

采用添加Al Ti B和四元复合变质剂对ZL101合金熔体进行处理,研究浇铸产品的力学和耐腐蚀性能。结果表明,Al Ti B和四元复合变质剂不仅能够抑制ZL101合金枝晶的生成,同时也具有良好的晶粒细化作用,加入量为0.5%,保温30 min后,在720℃浇铸变速箱的晶粒由平均150μm减小至62μm,并使合金的强度和伸长率分别提高27%和42%,同时提高ZL101合金的耐蚀性。Al Ti B和四元复合变质剂并不能改变硅形貌,将硅由未变质时的针状生长为球状或块状是Na F的作用。     

熔模铸件常见缺陷——化学粘砂与机械粘砂的分析及处理

化学粘砂和机械粘砂是指在铸件的表面上牢固地粘结着一层金属与型壳材料结合物,它是熔模铸件常见的铸造缺陷之一。通过阐述熔模铸件化学粘砂和机械粘砂的外部特征,产生的部位、机理以及主要原因,提出了从熔模铸造的选材、制壳工艺、焙烧工艺及熔炼工艺等方面采取实用有效的对策,从而提高熔模铸件的合格率。     

NbC颗粒对铜基复合材料性能的影响

以碳化铌颗粒和电解Cu粉为原料,采用微波烧结制备了不同质量分数的NbC颗粒增强铜基复合材料,通过对显微组织的观察和对密度、硬度和电导率的测试,探索了碳化铌质量分数、微波烧结温度对铜基复合材料性能的影响。。结果表明: 铜基体内NbC颗粒除少量颗粒团聚长大外,其他颗粒能均匀分布在基体上;随烧结温度升高,铜基复合材料的密度、导电率和硬度均有所增加;随增强相质量分数的增加,硬度增加,密度和电导率均明显下降;导电率在NbC质量分数为1%时,烧结温度影响较明显,烧结温度为1000℃时,导电率达到最大,此时为导电率为63.8IACS%。     

Microstructure and properties of heavily deformed Cu-Ag-Ce in situ nano-filamentary composite

The microstructure and properties of heavily deformed Cu-Ag-Ce in situ nano-filamentary composite were studied in this paper. As cast, copper matrixes were dendritic and Ag-rich phases, some of which present spheroidizing tendency, were embedded in Cu dentritic arms. After heavily deforming, Agrich phases develop into fibers: the thick fibers with a size of more than 50 nm and the thin ones with a size of less than 30 nm. Strengthening of Cu-Ag-Ce in situ nano-filamentary composite could be divided into two stages and the combination of different strength and conductivity could be obtained through controlling reducing area, intermediate heat treatment and stabilizing treatment. The results revealed that heavily deformed Cu-Ag-Ce in situ nano-filamentary composite had high strength ( ＞ 1.5GPa) and high conductivity(＞65 %IACS).     

Microstructure and properties of heavily deformed Cu-Ag-Ce in situ nano-filamentary composite

1 IntroductionIn recent years ,the high-strength and high-conductivity copper alloys produced by the co-deformationof two-phase structure using heavily deforming have been studied[1 -5]. According to the crystal type ,thematerials are dividedinto Cu-b.c .c .(body centered cubit ,such as Nb,Fe ,Cr) type and Cu-f .c .c .( facecentered cubit ,for example Ag) type . Previous study[7]indicates that Cu-Ag alloy containing less 6 %(mass fraction) silver is single phase Cu,the other alloys with mo…     

Microstructure and properties of heavily deformed Cu-Ag-Ce in situ nano-filamentary composite

The microstructure and properties of heavily deformed Cu-Ag-Ce in situ nano-filamentary composite were studied in this paper. As cast, copper matrixes were dendritic and Ag-rich phases, some of which present spheroidizing tendency, were embedded in Cu dentritic arms. After heavily deforming, Agrich phases develop into fibers: the thick fibers with a size of more than 50 nm and the thin ones with a size of less than 30 nm. Strengthening of Cu-Ag-Ce in situ nano-filamentary composite could be divided into two stages and the combination of different strength and conductivity could be obtained through controlling reducing area, intermediate heat treatment and stabilizing treatment. The results revealed that heavily deformed Cu-Ag-Ce in situ nano-filamentary composite had high strength ( ＞ 1.5GPa) and high conductivity(＞65 ,IACS).     

微合金化对铁基无磁中熵合金组织、力学和磁学性能的影响

采用水冷铜坩埚磁悬浮熔炼和铜模负压吸铸法制备了(Fe_63.3Mn₁₄Si_9.1Cr_9.8C_3.8)_100-xY_x(Y=Ag,Cu)中熵合金,通过XRD、SEM及VSM等研究了Ag和Cu微合金化对合金层错能、组织、力学和磁学性能的影响。结果表明,Fe_63.3Mn₁₄Si_9.1Cr_9.8C_3.8中熵合金为fcc结构,抗磁性元素Ag和Cu的添加进一步降低层错能同时细化晶粒,使得合金的屈服强度降低而断裂强度和塑性增加。(Fe_63.3Mn₁₄Si_9.1Cr_9.8C_3.8)_99.6Cu_0.4合金的断裂强度与塑性应变分别达到(2435±1)MPa和(22.2±0.1)%,相对磁导率低至1.00013,呈现出优异的力学性能和顺磁性。     

铝合金结构构件疲劳的探讨

 摘 要：铝合金相对于钢材和混凝土来说是一种新型的建筑材料,它具有自重轻、比强度高、可模性好、防腐蚀性能好、便于回收利用等优点,是可以大规模的用于建筑结构的理想材料,但是它也有一定的缺点,如温度敏感性比较强、抗疲劳性能差。本文介绍了铝合金材料在建筑结构中的应用,总结了铝合金在建筑结构中的疲劳问题,提出了控制和解决疲劳的方案,并对铝合金在建筑结构中疲劳问题提出进一步的研究方向。     

泡沫铝复合材料的制备及其阻尼性能

研究了新型轻质高阻尼泡沫铝复合材料的制备及其阻尼性能 ,通过在单纯泡沫铝孔洞中分别渗入松香、环氧树脂、环氧树脂加填料等高阻尼材料 ,制备出泡沫铝复合材料 ,然后研究它们的阻尼性能。实验研究表明 :与单纯的泡沫铝的阻尼性能相比 ,泡沫铝复合材料的阻尼性能明显优于单纯的泡沫铝的阻尼性能     

激光微织构化铝合金表面的摩擦磨损研究

采用脉冲Nd∶YAG激光器在铝合金试件表面加工出具有规则形貌的圆形凹坑阵列,借助HSR-2M型高速往复摩擦磨损实验机,在滑动速度为0.15m/s、载荷10N的条件下,考察了乏油条件下圆形凹坑表面微织构的几何参数对"球-面"摩擦副摩擦学性能的影响,分析了激光加工对铝合金表面显微硬度的影响,并采用超景深显微系统对试件及对偶摩擦副表面的磨损特性进行了研究。结果表明,激光加工提高了铝合金基底的显微硬度;在乏油条件下,微织构化铝合金表面的平均摩擦系数与无织构表面相比明显减小,且波动稳定;经磨痕形貌分析可知,微织构化铝合金表面磨损程度减轻,当微凹坑直径为60μm,即面密度为4.91%时,微织构化铝合金表面具有最佳的减摩、抗磨性能。     

微量Ti元素对Cu-Cr合金组织性能影响

本文采用大气熔炼制备了0.11Ti和0.21Ti含量Cu-Cr-Ti合金铸坯,经热轧-固溶-冷轧-时效工序制备带材,研究不同Ti元素添加量和热处理工艺对合金性能和组织的影响。结果表明,采用400℃/8h时效工艺,Cu-0.55Cr-0.11Ti合金具有较好的综合性能,其硬度、电导率和抗拉强度分别为125HV、72.3%IACS和517MPa,采用450℃/4h时效工艺,Cu-0.48Cr-0.21Ti合金具有较好的综合性能,合金硬度、电导率和抗拉强度分别为为126HV、52.3%IACS和523MPa,时效态两种合金在500℃保温1h硬度仍高于初始硬度85%;Ti元素含量的提高对时效态Cu-Cr合金的导电性能影响显著,Ti元素含量从0.11%提高至0.21%,峰值时效态合金的电导率提高了28.4%,Ti元素对合金硬度和强度的影响不大;Cr元素在Cu-Cr-Ti合金中的主要存在形式为第二相粒子,Ti元素的主要存在形式为溶质原子,立方相的形成是合金高温性能提高的主要原因。     

超轻镁锂合金LZ91热变形行为探究：本构方程及热加工图

本文以挤压态Mg-9Li-1Zn镁锂合金为材料在Gleeble3500热模拟实验机上做热压缩变形实验,变形温度范围为150℃-350℃,应变速率范围为0.001s-1-10s-1。基于所采集实验数据绘制流变应力应变曲线,建立了双曲线正弦函数的本构方程及真应变为0.916时热加工图,结合变形后微观组织观测分析了动态再结晶的产生情况,表明了适宜加工的安全区域和在加工中应该避免的失稳区域,预测温度范围为250-300℃,应变速率0.01s-1时为较理想的变形参数,峰值耗散系数值大于38.55%,热变形激活能Q=112.066kJ/mol,应力指数n=3.60273。     

大变形量挤压加工对Mg-11Al-3Zn组织及性能影响

采用大变形量挤压工艺制备了高性能Mg-11Al-3Zn镁合金.挤压变形可消除镁合金铸锭中的气孔、疏松和缩孔等缺陷;经热挤压后,晶粒显著细化,由铸态的120μm左右变为30μm左右.经挤压后合金的强度和塑性指标均有所提高.     

铝合金化学镀镍复合层工艺及性能研究

先将铝合金样品阳极氧化30 min,然后电镀铜5 min,最后化学镀镍30 min,可以在铝合金表面获得颜色稳定、结合性能良好的复合层,且复合层致密,厚度可达20μm以上,复合层的硬度HV0.025/20达到450以上.阳极氧化和电镀铜所用溶液相同,给生产带来了方便.     

激光照射对InSe结构及光电性质的作用研究

InSe具有高载流子迁移率,在光电探测和场效应器件应用上具有非常好的前景．但InSe易于氧化,特别是在一定光和热激发下会氧化成In²O³．在InSe的研究中,拉曼光谱、荧光光谱等手段均需采用激光进行激发,目前激光照射测试过程对测试结果的影响并不清楚．通过采用拉曼光谱、原子力显微镜和开尔文探针显微镜,详细研究了激光照射过程对InSe拉曼光谱测试、表面形貌和表面电势的影响．结果表明：在激光功率为0.20 mW、曝光时间10 s的条件下,激光照射对材料基本没有影响;随着激光照射功率增强,激光诱导表面氧化而产生结构形变,拉曼光谱峰强下降,表面电势升高;随着高激光功率照射时间增长,表面的氧化程度迅速增加,但拉曼强度呈现先下降后增长再下降的变化,其原因来自于氧化层形态的变化．光谱测试对InSe材料产生不可忽略的影响,在材料分析中需要给予重视．      

Ni3Al对CoCrFeNi高熵合金组织与性能的影响研究

设计了CoCrFeNi(Ni3Al)x（x=0.5,0.75,1,1.25）系列高熵合金,研究了合金的组织与性能,发现四种合金铸态时均为单相FCC固溶体。其中,铸态CoCrFeNi(Ni3Al)1.25具有最好的综合性能,屈服强度、抗拉强度、延伸率分别为420 MPa、867 MPa、21%。铸态合金经780℃、4h时效处理后,枝晶间析出大量40~50 nm的L12相,时效后,CoCrFeNi(Ni3Al)1合金时效后具有最好的综合性能,屈服强度、抗拉强度、延伸率分别为510 MPa、828 MPa、22%。研究表明Ni3Al的添加在适当范围内能够有效提高材料的强度,铸态时主要的强化方式是固溶强化,时效态主要是起析出强化作用。